Tank grating

ABSTRACT

A grating for use over opening means in armored cars, which grating has intercepting cup-shaped protrusions on opposite sides of the web members of said grating, in which the dimensioning of the respective local thickness of the cross sections of the rib members is effected in consideration of shelling directions which extend in a plane perpendicular to the longitudinal extension of the rib members but which otherwise extend in any direction with regard to the end face of the gratings in such a way that the path of possible shells are tangent to the front portions of the outermost end faces of the rib members while hitting side surfaces of the rib members at an angle Alpha , the applicable local steel thickness within the range of the projectile path hitting the rib members at an impact angle Alpha derived from that safety curve which in conformity with the impact angle Alpha indicates the wall thickness for that armor steel for which in conformity with the type and caliber of the projectile and of the firing weapon and the anticipated shelling distance safety against shelling is required.

United States atent 11 1 [111 3,901,124 Hausenblas Aug. 26, 1975 TANKGRATING napolis, Md., 1921, p. 485. [75] Inventor: l-lelmut Hausenblas,

Kassel-Kirch i m l m y Primary ExaminerStephen C. Bentley [73] AssigneezRheinstahl Henschel Attorney, Agent, or Firm-Walter BeckerAktiengesellschaft, Kassel, Germany [22] Filed: July 25, I973 57ABSTRACT 1 Appl 382349 A grating for use over opening means in armoredcars, R lated US. A li ti Dat which grating has intercepting cup-shapedprotrusions [63] cominuafiommpan of Sen 196'154 5, on opposite sides ofthe web members of said grating, 1971, abandonc in which thedimensioning of the respective local thickness of the cross sections ofthe rib members is [30] Foreign Application p i Data effected inconsideration of shelling directions which Nov 26 1970 German 2058169extend in a plane perpendicular to the longitudinal ex- I y tension ofthe rib members but which otherwise ex- [52] U S Cl 89/36 109/49 5 tendin any direction with regard to the end face of [51] i 6 the gratings insuch a way that the path of possible [58] Field IIIIIIIII 109/49 5Shells are tangent to the front portions of the outerg 180/68- most endfaces of the rib members while hitting side surfaces of the rib membersat an angle a, the applica- [56] References Cited ble local steelthickness within the range of the projectile path hitting the ribmembers at an impact angle a UNITED STATES PATENTS derived from thatsafety curve which in conformity 3,586,236 6/1971 Schafflcr 89/36 L iththe impact ang]e indicates the wall thickness FOREIGN PATENTS ORAPPLICATIONS for that armor steel for which in conformity with the l 159816 12/963 Grman 109/495 type and caliber of the projectile and of thefiring l l84 675 l2/l964 German; I:I:3:11:13: 109/495 weapon and theanticipated shelling distance Safety against shelling is required.

3 Claims, 5 Drawing Figures sum 1 o 3 PATENTEU W92 5 I975 PATENTEUAUB25|975 3,901,124

SHEET E OF 3 Fig.1 b

PATENTED AUG 2 6 I975 sum 3 u F 3 Fig.2

o impact angle 0C 0 Fig.3

TANK GRATING This is a continuation-in-part of co-pending U.S.application Ser. No. 196154 Hausenblas filed Nov. 5, 1971 now abandoned.

The present invention relates to a grating for use as tank gratinghaving cup-shaped intercepting protrusions on its elements for blockinga rectilinear passage of projectiles, splinters or similar bodiesthrough the grating, while the cross section of the ribs toward theoutside of the grating is thicker than the further inwardly locatedsmaller cross-sectional thickness and while the outer end face of theribs is of an overall convex coutour and the rib cross section withinthe region of its smaller thickness is provided with cup-shapedintercepting protrusions extending toward different sides of the ribs.

With tank gratings of this type it is assumed that the projectiles andsplinters to be blocked, unless they hit the tank perpendicularly, willimpact upon the grating only at a limited relatively small angle withregard to the surface of the grating. The dimensioning is so selectedthat with a substantially horizontal or only slightly inclinedarrangement of the grating on the armored vehicle, an energy-loadedprojectile arriving at the usually maximum angle of elevation withregard to the grating surface will impact upon the thick portion of therib cross section. However, in many instances it becomes necessary toprovide gratings also on parts of the vehicle on the stern and on theside walls of the armored vehicle. Frequently the lack of space makes itnecessary to place the gratings on the vehicle surface. However, theassumption that the projectiles and splinters to be intercepted hit thegrating at a limited relatively small angle only with regard to thegrating surface no longer applies with this arrangement. In other words,when mounted at these areas, the gratings with the usual dimensions willbe pierced because the projectiles will hit at an angle which isdifferent from the angle on which the dimensioning was based.

It is, therefore, an object of the present invention so to improve thecross-sectional shape of the grating bars as they have become known byGerman Pat. No. 1,159,816 that the gratings will also when shot at underany steep angle with regard to the grating surface be able to blockprojectiles and splinters in the same manner as the surrounding walls ofthe vehicle while at the same time a loss in pressure of the incomingand outflowing air will be as low as possible.

These and other objects and advantages of the invention will appear moreclearly from the following specification in connection with theaccompanying drawings, in which:

FIG. 1 shows a longitudinal section through an armored plate with anopening having across thereof arranged a grating according to theinvention, said section being taken along the line II of FIG. la.

FIG. 1a is a top view of FIG. 1.

FIG. lb is a cross section through a grating according to the inventionwith three bars, said section being taken along the line IbIb of FIG.1a.

FIG. 2 shows the principal course of a safety curve of a tank steel; thethickness d of the tank steel plate in millimeters is represented as afunction of the impact angle a in degrees.

FIG. 3 is a cross section through a tank steel plate having a thicknessd and having associated therewith the impact angle a on the uppersurface of the tank steel plate.

The problem outlined above has been solved according to the presentinvention by the fact that, while maintaining the structure of thecross-sectional shape of the grating bars with outwardly located thickhead portion, with adjacent rib-like extensions substantially verticallylocated with regard to the surface of the grating and with at least twointercepting cup-shaped protrusions according to German Pat. No.1,159,816 provided on alternate sides of these ribs, all cross-sectionalparts of the grating bars are as to their local thickness so dimensionedthat they meet the requirements with respect to the minimum values aslisted in the so-called safety curves for tank steel sheets, while, totake into consideration the severest conditions, shelling directions areassumed which extend in a plane perpendicular to the longitudinalextension of the grating bars, but which otherwise extend in any desireddirection with regard to the end face of the gratings, and while theprojectile paths are tangent to the front portion of the bar headportions. Inasmuch as the safety curves, in addition to the quality ofthe tank steel, also depend on the caliber and the type of the impactingprojectiles as well as on the fighting distance, in each instance thatparticular curve for the quality of the tank steel to be used is to beemployed for the dimensioning which corresponds to the respective typeof projectile, caliber and fighting distance against which the tankgrating is to be safe-guarded.

A particularly advantageous design of the grating according'to thepresent invention will be realized by making the thickness of the headportions of the grating bars measured in the direction of the gratingsurface, in a manner known per se, substantially equal to half the pitchof the grating bars, and by selecting the width of the cup-shapedintercepting protrusions as measured parallel to the surface of thegrating in such a way that it will be impossible in any shellingdirection to place a straight line as tangent to the cross section ofthe bars which line will not at any other place intersect or at least betangent to the contour of another portion of a cross section of a bar.

By the selection according to the present invention of the ratio of thethickness of the head portions to the pitch of the grating bars it willbe assured that the projectiles, which arrive at steeper angles withregard to the surface of the grating and which hit the grating barsbelow their head portions, will hit the surface of the bars atrelatively flat angles so that in conformity with the above referred tosafety curves relatively thin material thickness will suffice to preventa piercing. In this way a particularly favorable weight of the gratingis obtained.

For keeping out liquid, burning substances, especially chemical warfareagents, it is suggested according to a further development of thepresent invention to provide the lateral confining walls of the gratingwith discharge openings which originate at the cavities of thecup-shaped protrusions and which discharge such substances to theoutside of the vehicle. If it is desired to realize as slight a loss inpressure as possible of the air or gas passing through the gratings, thecup-shaped protrusions are to be filled in with a filling substancewhich is mechanically less resistant so that splinters can withoutdifficulties enter into the filling substance and are retained therein.

According to a further development of the invention, the surface of thefilling substance may be painted in such a way that an as smooth aspossible surface is obtained which will result in the lowest possiblefriction losses for the air passing through.

Referring now to the drawings in detail, FIG. 1 shows an armored plate100 with an opening 101 across which extends the grating according tothe invention which grating comprises a plurality of grating bars acutout of which only with the bars 102, 102', 102" and 102" being shown.These grating bars, the cross section of which is illustrated in FIG.1b, are connected to the frame parts 103, 103 at 104, 104', 104" and104" by zinc plating and welding. If desired one or more intermediatesupporting bars 105 or the like may be provided to which the gratingbars are likewise connected by zinc plating and welding. The connectionof the grating to the armored plate 100 is effected by means of theframe bars 103, 103' of said armored plate. To this end there isprovided a hinge which comprises an element 107 welded to the frame part103, the elements 108, 108 welded to the armored plate 100, the bolt109, and the cotter pin 110. On the other side the grating is connectedto the armored plate 100 by means of an element 111 which is welded tothe frame part 103' and has a bore 11 1a through which passes a screwbolt 112 threaded into a threaded dog 113 which is welded to the armoredplate 100.

As will be seen from FIG. 1b showing the tank grating of the inventionin cross section with a head edge portion 1, the bars of the tankgrating are provided with a rib-like extension 2 substantiallyperpendicular to the grating surface 3 while two intercepting cup-shapedor hook-shaped in cross section protrusions 4 and 5 are arrangedalternately on opposite sides of the ribs. Lines 6 and 7 representprojectile curves of all possible directions or angles ,8 which in eachinstance are tangent to the thick head 1 of the grating bars and whichthen within the grating impact upon the surface of the bars at differentangles a. In other words, the angles B indicate the flight path of theprojectile relative to the surface of the grating.

The known definition of the impact angle a between the direction of theprojectile curve 10 and the surface of the tank plate 11 with thethickness d is illustrated in FIG. 3. FIG. 2 shows the basic form of theknown safety curves which indicate the minimum thickness d of the tanksteel plate depending on the impact angle a which thickness is necessaryto prevent the piercing of the tank steel plate of a certain tank steelthickness, for a certain projectile caliber, for a certain type ofprojectile, and at a certain fighting distance. Wherever the surface ofa grating bar is hit in conformity with the projectile curves 6 and 7,the thickness d of the tank material therebehind is, according to thepresent invention, depending on the local impact angle a to bedimensioned in such a way that the safety requirements of FIG. 2 are metin conformity with the given values of the above referred to parametersof HG. 2. The thickness of the ribs is provided by inclining the surfaceof the rib having the hook-shaped protrusion 4 from the head edgeportion 1 to the protrusion, while the opposite surface is similarlyinclined from the head edge portion and then inclined away from thefirst surface to the hook-shaped protrusion 5.

Such safety curve, which is obtained by the shelling of tank steelplates, can approximately be expressed by the equation d do X sin a, inwhich do is a constant depending on the quality of the respective tanksteel and the above referred to parameters. The range in which thiscurve applies relates to the customary values of a only. If all valuesof a are to be covered for certain calibers,'types of projectiles andfighting distance, this curve is ascertained from shelling tests.

Additionally, linings 8 and 9 illustrated in FIG. 1b by dot-dash linesand consisting of a light filling substance of low mechanical resistancemay be provided which will not affect the guide lines for thedimensioning of the steel cross section and which may aid therequirement concerning splinter safety and low pressure loss. Suchlinings may consist of a strip of synthetic material, e.g. foamedsynthetic material such as foamed rubber material, of a synthetic masssuch as polyurethane, adapted to be applied by painting or spraying. Thesynthetic strips may be connected to the steel grating bars by anysuitable synthetic adhesive or cement, whereas the synthetic mass itselfhas adhesive properties so that it adheres by itself to the walls of thegratings to which it has been applied.

There is noted a foreign German Pat. disclosure No. 1,184,675 whichactually concerns an addition to a foreign German Pat. No. 1,159,816belonging to the assignee of the present invention. According to theadditional patent disclosure of German Pat. No. 1,184,675 the cup-shapedprotrusions with the grating used as armor grating becomes filled-outwith a filling mass that is relatively light and capable of littleresistance mechanically.

Nothing is mentioned in the additional patent about the structuring ofthe ribs (grating webs) consisting of armor steel. The parent GermanPat. No. 1,159,816 includes in contrast as teaching the statements aboutthe suitable constructive embodiment of the grating webs. Because of thepredetermined utilization of these gratings at that time upon the roofof a vehicle there only would have to be considered elevational angle ofthe arriving shots with respect to the grille or grating upper surfaceup to only a relatively low boundary value. These shots accordinglyalways only hit upon the thick head portions of the grating webs; forthis reason in the corresponding patent disclosure there was providedonly a corresponding predetermined dimensioning of the thickness thereofin order to hinger the penetration of the head portions of the webs orstruts. For the ribformed web parts lying below the head portions and atlocations adjoining the adjacent cup-shaped projections which formerlycould be hit only by shrapnel or shot splinters, no further featureswere prescribed about the formation thereof in addition to thedisclosure already given because of the essentially smaller energy ofthese splinters. After subsequently the gratings had to be used on moreor less vertical vehicle walls, for instance as rear-cover gratings, theaforementioned limits as to the elevational angle of the arriving shotsno longer applied which means that the grille or gratings could be shotupon as far as a location at right angles to the upper surface thereof.Now the rib-type portions and the cup-shaped protrusions could be hitnot only by splinters of shots damaging the head portions but ratheralso by shots arriving directly with full energy (not dispersed or splitup). Consequently the concern no longer involved the form of therib-formed and cupshaped protrusion in contrast to the statements of theprior foreign German disclosure No. 1,159,816, but

rather also the concern must be emphasized as now being with thenot-mentioned dimensioning of these web portions. For this reason thepresent disclosure includes and covers the dimensionally prescribedmeasures for the entire portions collectively.

The features of the present invention are given without fixing orrestricting the same to a particular caliber, speed and type of thearriving shots as well as the quality of the armor steel used for thegrating webs or struts to the extent possible. These paraticularly arethe parameters upon which the mentioned safety characteristic or curvesfor armoring would be dependent.

The foreign German disclosure No. 1,114,410 describes a cover grating orgrille for cooling air openings with an armored military vehicle, Thisknown cover grille or grating consists of a number of scale-like orshed-type baffles or sheet metal deflectors of armor steel engaging overeach other whereby each baffle or deflector plate has both a dome orpeak and also a cup or shell adjoining therewith. Hereby the concern,however, is with a roof of a vehicle having a cover grille or gratingarranged therewith as can be recognized especially from the illustrationof FIG. 7. At most the earlier embodiment would have outlet openingswith the cover grille or grating which would seem similar to those ofthe present disclosure.

The grating webs with the prior German disclosure No. 1,159,816 are soembodied that the shots arriving at different angles (as far as to thementioned boundary value of the shown angle) directly always only hitthe compacted head portion of the grating web whereby the shots split upand splinter into various directions. Thus as mentioned previously therib-formed portions with the cups or catching shells located below thehead portions could now only be met by shot splinters. Since splintersare known to have considerably less penetrating capability than shotsthat are not split up, the ribformed portions and the cups or catchingshells of the grating webs were dimensioned to be more weak and notaccording to the safety curves or characteristics that apply for shotsthat have not been split up.

Rear cover grilles or gratings in contrast to roof gratings for instancecan be subjected to shots which will hit more or less at right angles tothe surface thereof so that these rear grilles or gratings also must bemade safe, consequently the ribformed parts of the grating webs orstruts can be hit together with the catching shells or cups by shotsthat are not split up; since the same can be hit now not only by shotsthat have been sg i t up but rather by direct hitting shots, it becomesnecessary in contrast to the statements of the German disclosure No.1,184,675 to embody the rear grille or grating in according with thefeatures of the present invention. The present case discloses how thesame should be embodied to comply with the safety curves orcharacteristics. This represents an essential part of the teaching ofthe present invention and cannot be disregarded as being unessential andwithout purpose.

In summary, there can be noted that the essential concept of the presentinvention that the grating or grille was provided at the vehicle rearshould be embodied aside from the vehicle roof so that also for shotsencountered at every suitable steep angle for grating or grille uppersurface protection will be provided.

The gratings used for covering up openings in armored vehicles consistsin essence of ribs having profiled cross section and these hinderingstraight-line passage of shots, splinters and the like. A possibilityexists that shots fly closer to the head part of the grating webswhereby material is struck out of the head part. Thus the featuresconcerning the described tangential relationship and the like of shotpaths can be considered to be an essential factor influencing therequirements for safety of the grating believed to possess inventivenessin a general sense.

The safety characteristics or curves taken into consideration as far asknown to be pertinent to armor steel plates are implicitly pertinent toa precondition of constant plate thickness as to the part subject tobeing hit by shots. The corresponding characteristic or curves forarmor-steel casting are also applied only for very conventional armorthickness conditions. With the grating webs or struts according to thepresent invention in contrast the dimensional wall thicknesses changevery quickly as shown by FIG. 1 of the drawings. There occurredaccordingly the question whether the angle of impact relative to thesteel outer surface hit by the shot or relative to the middle line ofthe steel thickness should be counted. While with conventional wallthicknesses there can be neglected any changes in the difference thereofwith respect to both angles, the same is no longer true for the presentcase. The fixing of the measurement of the angle relative to the hitsteel armor surface proceeds from the concept that the penetratingprocedure of the shot becomes determined in essence from the first phasethereof, in other words, shortly after impact of the shot. Suchconsideration involves an inventive feature which would not be obviousand in a desirable sense and for partial compensation of theconsequences with respect to the strict safety requirements set forthpreviously would lead to thinner steel cross-sectional thickness andtherewith result in a lighter embodiment of the grating webs or struts.Test results have shown that grating webs or struts so dimensioned arenot embodied too weak with respect to the ballistic protection.

In order to hinder that shots or splinters repelled by the ribs willpenetrate into the vehicle inner chamber, there is already known in theGerman disclosure No. 1,159,816 to provide a particular cup-shapedconfiguration of the ribs of the grating; and the further cited foreignGerman disclosure No. 1,184,675 shows filling out of the cup-shapedconfigurations with toughresilient work material as an additionalsplinter protection. With the cited foreign German disclosure No.1,159,816, it is apparent that the thinner grating web or strutcross-sections apparently are not dimensioned according to the teachingof the present invention as readily recognizable from a comparison ofthe representation of what is known with respect to the teaching of thepresent invention. This was also not necessary with the prior embodimentsince at that time the thinner grating web or strut parts in view of theprecondition that shots are to be expected only at a predetermined anglerelative to the grille or grating outer surface was such that the samewould be struck only by splinters at the head portion of the gratingwebs or struts when shattered shots were to be taken into considerationonly for protective purposes whereas now direct shots that are notshattered or splintered are thereby taken for protective purposes. Agrating with grille or grating webs or struts according to the presentinvention is to hinder penetration of shots, shot splinters and the likeinto the vehicle interior both during direct flight and also duringrebound or ricochet conditions regardless of the direction from whichthese foreign bodies come and on the other hand the same are to providethe smallest possible flow resistance as to passage of airthere-through.

Thereby that there is hindered that the shots or splinters can penetratethe grating during direct flight or during repelling (the shots orsplinters would for instance have to be repelled twice, one after theother) the effectiveness of the same in general should be very muchweakened since the remaining energy of the shots or splinters becomesdestroyed. Advantageously there is also effected that the grating isembodied in a technically simple manner to produce and having aweight-saving formation whereby also the danger of an undesiredreduction of air passage therethrough becomes extensively avoided.

In summary, there can be noted that there is provided a cover grille orgrating to be used as armor for openings on armored vehicles. Theaxially parallel struts or webs of the grille on the side away from thevehicle each have a thickened head embodied on the face surface;adjoining thereto the same rib-formed extensions or protrusions arelocated substantially at right angles to the grille outer surface and onboth sides providing cup-shaped or catching shell portions whichsuitably are filled out with tough resilient work material as additionalsplinter protection. Thereby the foregoing is further characterized inthat the spacing of the grating webs or struts located substantiallyhorizontally in the vehicle rear portion becomes so selected withrespect to each other under consideration of the shot paths (6, 7) of adirect or repelled flight for a shot, foreign body and the likeencountered thereby such that the flight path in every case is blockedby one of the rib-formed protrusions or extensions (2) of one of thegrating webs or struts. The foregoing takes into consideration a planelocated at right angles to the grating web or strut longitudinaldirection but otherwise the same extended in suitable direction withrespect to the grille outer surface (3) that the shot paths (6, 7) aretangential to the heads (1) of the grille or grating struts or webs andthe rib-formed protrusion or extension of each grating strut or webprovides a thickness (d) dependent upon impact angle (alpha) between theshot path (10) and the grating strut or web.

It is, of course, to be understood that the present invention is, by nomeans, limited to the particular showing in the drawings but alsocomprises any modifications within the scope of the appended claims.

What I claim is:

1. A grating for protecting openings in the sides and ends of armoredvehicles, which includes a plurality of rib members arranged inparallel, spaced relation to each other and perpendicular to the gratingsurface, said rib members being thickest at the head edges adjacent saidsurface of said grating and substantially as thick as the spacingbetween said head edges portions, each of said rib members having aprotrusion hookshaped in cross section on one surface at its centralintermediate portion-and a second protrusion hookedshaped in crosssection on the other surface at the edge opposite said head edgeportion, each of said protrusions forming a channel opening toward saidhead edge portion, said other surface being curved from said head edgeportion to said intermediate portion and then inclined from saidintermediate portion away from said one surface to said hook-shapedprotrusion at the opposite edge, said one surface being inclined fromsaid head edge portion in the same direction as said other surface tosaid intermediate protrusion, said intermediate protrusion of each ofsaid rib members extending to a transverse plane passing through thesurface of the head edge portion of an adjoining rib member, saidintermediate protrusion being substantially equal in thickness to thethickness of said intermediate portion of said rib member, said headportion, intermediate portion and protrusions being of a thickness atevery point of impact of missiles as to provide resistance topenetration at the maximum angle of impact according to a curve of themaximum thickness for resistance to penetration at the maximum angle ofimpact of a missile at that point.

2. A grating in combination according to claim 1, which comprises outletopenings in the lateral confinements of said grating, said outletopenings extending from the cavity of said intercepting hook-shapedprotrusions in the direction toward the exterior of the armored vehicle.

3. A grating in combination according to claim 2, in which saidintercepting hook-shaped protrusions are lined with a low-weight fillingmass of synthetic foam with low mechanical resistance adhering thereto.

1. A grating for protecting openings in the sides and ends of armored vehicles, which includes a plurality of rib members arranged in parallel, spaced relation to each other and perpendicular to the grating surface, said rib members being thickest at the head edges adjacent said surface of said grating and substantially as thick as the spacing between said head edges portions, each of said rib members having a protrusion hookshaped in cross section on one surface at its central intermediate portion and a second protrusion hooked-shaped in cross section on the other surface at the edge opposite said head edge portion, each of said protrusions forming a channel opening toward said head edge portion, said other surface being curved from said head edge portion to said intermediate portion and then inclined from said intermediate portion away from said one surface to said hook-shaped protrusion at the opposite edge, said one surface being inclined from said head edge portion in the same direction as said other surface to said intermediate protrusion, said intermediate protrusion of each of said rib members extending to a transverse plane passing through the surface of the head edge portion of an adjoining rib member, said intermediate protrusion being substantially equal in thickness to the thickness of said intermediate portion of said rib member, said head portion, intermediate portion and protrusions being of a thickness at every point of impact of missiles as to provide resistance to penetration at the maximum angle of impact according to a curve of the maximum thickness for resistance to penetration at the maximum angle of impact of a missile at that point.
 2. A grating in combination according to claim 1, which comprises outlet openings in the lateral confinements of said grating, said outlet openings extending from the cavity of said intercepting hook-shaped protrusions in the direction toward the exterior of the armored vehicle.
 3. A grating in combination according to claim 2, in which said intercepting hook-shaped protrusions are lined with a low-weigHt filling mass of synthetic foam with low mechanical resistance adhering thereto. 